Mushrooms are fascinating organisms with unique flavors, textures, and nutritional values. Depending on where you live, you may already have a wide selection of mushroom that are more exotic than your common button mushrooms at your grocery store. And if you venture into the woods, you may find even more rare species that are not widely commercially available.

If you're a mushroom enthusiast, you may have considered cloning your favorite wild or store-bought mushrooms to grow at home. Cloning mushrooms on agar petri dishes is a popular method that can help you build a library of different mushroom strains that you can revisit and grow in the future. Paul Stamets, and many mycologists like him, spend their free time foraging the woods for new mushroom specimens to bring home, catalogue, and clone. In this blog post, we'll guide you through the steps involved in cloning mushrooms on agar petri dishes.

Step 1: Prepare the Agar

Agar is a gelatinous substance derived from algae that provides a nutrient-rich medium for mushroom growth. To prepare agar petri dishes, you'll need to mix agar powder with water and heat the solution until the powder dissolves. Make a 2% agar plate, meaning mix 20g of agar into 1000ml of water. You can add malt extract, potato dextrose extract, or high-fructose corn syrup to the agar to provide a supplemental food source for your mushroom sample to grow on.  Depending on the mushroom species you are trying to isolate, you may want to experiment with different types of nutrients, as different mushrooms will prefer different food sources. Once the agar has cooled to around 50°C, pour it into sterile petri dishes and allow it to solidify.

Step 2: Isolate Clean Tissue

The first step is to isolate clean tissue from your mushroom sample. If you're using wild mushrooms, you'll want to choose a fresh, healthy specimen and remove any dirt or debris. For store-bought mushrooms, simply remove a small piece of the cap or stem. To ensure you're starting with clean tissue, you will want to cut into the mushroom itself and extract out a piece of mycelial tissue from inside the mushroom (that is not exposed to the outside). To do this, sterilize a scalpel until it is red hot. Let the blade cool down, then slice into the mushroom, and remove a small piece of the mushroom flesh.

Step 3: Plate the Tissue

Using the same sterile scalpel, place your clean mushroom tissue onto the agar surface of the petri dish. Be sure to handle the tissue as little as possible to minimize the risk of contamination. When you are plating, make sure to lift the lid of your petri dish as little as possible to create the smallest opening. This will reduce the chance of contaminants in the air from landing on your agar. You can plate multiple pieces of tissue onto the same dish to increase your chances of a successful clone.

Step 4: Incubate and Observe

Once you've plated your mushroom tissue, seal the petri dish and incubate it at the optimal temperature for your chosen mushroom species. Depending on the variety, this could be anywhere from 20-30°C. Over the next few days or weeks, you should start to see growth around the edges of the tissue. This mycelial growth is a sign that your clone is taking root.

Step 5: Transfer to Grain or More Agar

Once you have mycelial growth, you can transfer the tissue to a more nutrient-rich substrate, like sterilized grains or another agar petri dish. This will allow the mycelium to continue growing and maturing. Transferring your tissue to another petri dish also helps to isolate your mushroom from any potential contaminants that were transferred with your sample in the first plating. These contaminants may lie dormant for a while, but can wake up a few months down the line. The second plating is a good way to ensure you are reducing the contaminant load on your mycelial sample. By repeating this process, you can build a library of mushroom strains that you can cultivate at home.

Cloning mushrooms on agar petri dishes is a rewarding and exciting process that allows you to explore the diversity of mushrooms and cultivate your own unique strains. By following these simple steps, you can create a collection of mushrooms that you can grow, experiment with, and enjoy for years to come. Happy cloning!

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